My 68 (393W) is pinging!

Crs

Member
May 7, 2004
182
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16
San Francisco, CA
I've noticed that my car has been pinging(full throttle) after i changed my plugs(autolite 135) and distributor Pro billet MSD). I wanted a 1 step hotter plug since my plugs were black, so i tried some AC delco's. Could this be a the plugs causing this pinging or a timing issue? Timing is at 10 initial and 38 total.
 
If it didn't ping before and now it is I would say it has something to do with it. Maybe your running to rich and thats why its fouling the plugs. Try switching back to the old plugs and see what does for you. Whats your compression?
 
Crs said:
My Comp is 10.2 to 1. The plugs seem to be burning the right tan color now since the hotter step up.

Some other ideas if the pinging continues.

Try purchasing your "super" gas at a different gas station.

You might also want to have your distributor recurved to better match you combination.

A third option would be to retard the timing a couple of degrees.
 
Just for comparrison I run 10.3ish:1 compression with the stock autolites which I think are the number 5 heat range which look pretty hot with out pinging and I ran more timing than you. I've since switched to 2 range colder plugs and plan to use a retard box just because I'm going to throw nitrous to it later.
 
I for one have never heard what a ping sound like, I am in the process of building my first engine. I know it probly sounds like a ping. But is it high pitched? I would assueme so, but I dont think I could hear it over my exhauts (FM 40's). Is it loud? I know what ping is from reading about it, but what dose it sound like?

Yeah, I know random and off topic.

Tyler
 
Think of it like this, its basically 2 explosions hitting each other. You'll hear it over your 40s.

The diffrent gas, do you not have 93 octane? If that doesn't work I would switch back to the old plugs and see if the pinging goes away. If it does then tune to unrich. You might also try bringing in your timeing later if your bringing it all in by 2500 like most of us.
 
steel1212 said:
Think of it like this, its basically 2 explosions hitting each other. You'll hear it over your 40s.

The diffrent gas, do you not have 93 octane?

Pinging usually involves the piston trying to compress those explosions, too.

Frisco = California = only 91 unless you mix in some of your own Toluene, but that gets cost prohibitive real quick.